Specialized midline precursors of the developing Drosophila embryo give rise to specific sets of neurons and gila, and serve as an excellent model system for the study of CNS development and function. Using available data, our lab has constructed a database of 297 putative midline-expressed genes. Since the exact expression patterns of a majority of these genes are unknown, a major goal of this proposal is to use high throughput RNA in situ hybridization to map the expression patterns of these genes during CNS midline development. This analysis will provide (1) a refined molecular map of the midline CNS and (2) serve as a reference for the analysis of midline CNS gene transcription. To determine which of these genes are involved in glial development, midline-glial-expressed genes will be functionally screened for glial phenotypes using RNA interference and available genetic mutants. For glial genes encoding transciption factors, in situ expression pattern screening and microarray analysis will be used to identify transcriptional changes in mutant genetic backgrounds. This analysis will provide a clearer understanding midline CNS development and the transcriptional pathways that regulate midline glial development and function. [unreadable] [unreadable]